Planning Investigations

Overview

In this 60-minute lesson, students will learn to plan a scientific investigation by identifying variables and structuring a clear procedure. The lesson builds foundational scientific inquiry skills aligned with the National Curriculum for England (Year 9), focusing on working scientifically: planning, variables and control, and procedural development.

National Curriculum Links

This lesson meets the following National Curriculum requirements for Science at Key Stage 3 (Years 7–9):

• Plan enquiries, including recognising and controlling variables where necessary (Working Scientifically)
• Present observations and data using appropriate methods
• Apply scientific knowledge and understanding to explain experimental procedures

Learning Objectives

By the end of this lesson, students will be able to:

• Identify independent, dependent, and controlled variables in a given scientific scenario
• Explain the importance of controlling variables to ensure a fair test
• Construct a clear and logical plan for a scientific investigation

Success Criteria

• Correctly identify the independent, dependent, and controlled variables in an experimental context
• Produce a structured investigation plan outlining steps, variables, and controls
• Demonstrate understanding of why controlling variables is essential for valid results

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Lesson Structure

Starter (10 minutes)

Activity: Variable Detective

• Present students with a simple experimental scenario (e.g., effect of light intensity on plant growth).
• In pairs, students list variables they think are involved.
• Whole-class discussion to classify and confirm the independent, dependent, and controlled variables.
• Use a mini whiteboard or digital polls to make this interactive and engage all learners.

Teacher Tip: Use varied examples (biology, physics, chemistry) to cater to different interests and highlight cross-topic scientific skills.

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Main Teaching (20 minutes)

1. Explanation and Modelling (10 minutes)

• Explain definitions of independent, dependent, and controlled variables with clear examples.
• Emphasise the importance of controlled variables for a fair test and reliable data.
• Introduce a simple step-by-step approach to writing a procedure for an investigation:

1. Define the question/hypothesis
2. Identify variables
3. Outline materials and apparatus
4. Describe stepwise procedure ensuring reliability and control
5. Plan data collection method
6. Consider safety and ethical points

• Model writing a plan, using an example focused on testing reaction time with caffeine intake or similar relatable topic.

2. Think-Pair-Share (10 minutes)

• Provide a new investigation prompt (e.g., effect of temperature on solubility).
• Individually, students identify variables.
• Discuss in pairs to outline a simple plan referencing the steps modelled.
• Select a few pairs to share their plans and receive peer/teacher feedback.

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Activity (20 minutes)

Group Task: Investigation Planning

• In groups of 4-5, students are given different investigation scenarios linked to the broader unit on scientific enquiry.
• Each group writes a clear plan using the six-step structure introduced. They must highlight their variables and control strategies explicitly.
• Groups prepare a one-minute summary to share key points of their plan.

Differentiation:

• Provide scaffolded templates for students requiring additional support,
• Challenge higher-ability students to add considerations for reliability, repeatability, or alternative methods.

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Plenary (10 minutes)

Class Discussion & Self-Assessment

• Discuss how controlling variables affects validity and reliability of investigations.
• Recap the importance of a clear plan before practical work.
• Individual reflective task: students complete a “Success Criteria Checklist” matching objectives with their own learning from the lesson.
• Encourage students to write one question or uncertainty they still have about planning investigations for follow-up in next lessons.

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Assessment

• Formative: Variable classification during starter; peer-teacher feedback on group plans
• Summative: Completion and accuracy of individual success criteria self-assessment; quality of written investigation plan

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Resources

• Scenario cards describing simple investigations
• Whiteboards or paper for variable identification
• Investigation planning template handouts
• Mini whiteboards or digital quiz tools for engagement

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Differentiation and Extension Ideas

• Lower ability: focus on identifying variables correctly with sentence starters
• Higher ability: critique sample plans for weaknesses in controlling variables
• Extension: Introduce basic risk assessment or ethical considerations in investigation planning

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Teacher Notes

• Emphasise scientific vocabulary for variables and procedure planning throughout.
• Ensure active student participation and frequent checking for understanding.
• Build connections between this skill and upcoming practical lessons for seamless application.

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This lesson provides a strong foundation for the next stages in the unit “Exploring Scientific Inquiry” by embedding essential planning skills, promoting critical thinking about variables, and practising procedural clarity, all directly supporting key requirements of the National Curriculum for England at Key Stage 3.